These are historical forms of Celtic languages and would be useful for etymologies.
oco (Old Cornish)
- Wikidata item: https://www.wikidata.org/wiki/Q48304520
- Existing lexemes: https://www.wikidata.org/wiki/Special:WhatLinksHere/Q48304520?namespace=146
- ISO 639-3: https://iso639-3.sil.org/code/oco
- BCP 47: https://r12a.github.io/app-subtags/index?check=oco
cnx (Middle Cornish)
- Wikidata item: https://www.wikidata.org/wiki/Q12642603
- Existing lexemes: https://www.wikidata.org/wiki/Special:WhatLinksHere/Q12642603?namespace=146
- ISO 639-3: https://iso639-3.sil.org/code/cnx
- BCP 47: https://r12a.github.io/app-subtags/index?check=cnx
owl (Old Welsh)
- Wikidata item: https://www.wikidata.org/wiki/Q2266723
- Existing lexemes: https://www.wikidata.org/wiki/Special:WhatLinksHere/Q2266723?namespace=146
- ISO 639-3: https://iso639-3.sil.org/code/owl
- BCP 47: https://r12a.github.io/app-subtags/index?check=owl
wlm (Middle Welsh)
- Wikidata item: https://www.wikidata.org/wiki/Q2487263
- Existing lexemes: https://www.wikidata.org/wiki/Special:WhatLinksHere/Q2487263?namespace=146
- ISO 639-3: https://iso639-3.sil.org/code/wlm
- BCP 47: https://r12a.github.io/app-subtags/index?check=wlm
Already done (as part of T341409)
sga (Old Irish)
- Wikidata item: https://www.wikidata.org/wiki/Q35308
- Existing lexemes: https://www.wikidata.org/wiki/Special:WhatLinksHere/Q35308?namespace=146
- ISO 639-3: https://iso639-3.sil.org/code/sga
- BCP 47: https://r12a.github.io/app-subtags/index?check=sga
mga (Middle Irish)
- Wikidata item: https://www.wikidata.org/wiki/Q36116
- Existing lexemes: https://www.wikidata.org/wiki/Special:WhatLinksHere/Q36116?namespace=146
- ISO 639-3: https://iso639-3.sil.org/code/mga
- BCP 47: https://r12a.github.io/app-subtags/index?check=mga